Just set some arbitrary size, say 50 cny to buy on dips. Sell half on 50 cny rallies. Or some other rule for retracements to buy dips, and to exit.
I have a few rules like that from my trading strategy.

Right now the trend has been confirmed, as per the time at mode methodology, and I have a time and price target for it. So, I have to maneuver it safely. One core position will be held all the way up, and with part of the funds I'll play the retracement, buying dips mostly.